Cleanup for C++20 testing on a Mac M1

This patch supplies additional cleanups that were independently
developed testing C++20 on an M1 mac.  After rebasing onto the
changes already landed in `master`, the main effect is to adopt
an additional library feature macro, in the style of existing
feature macros, rather than rely on inline tests for the C++
language version.  Also added platform support for the Arm 9 CPU,
and fixed up a typo or two.

groups/bsl/bsl+bslhdrs/bsl_functional.h

@@ -27,7 +27,6 @@ BSLS_IDENT("$Id: $")
 namespace bsl {
 
     // Import selected symbols into bsl namespace
-    using std::binary_negate;
     using std::divides;
     using std::greater;
     using std::greater_equal;
@@ -40,13 +39,10 @@ namespace bsl {
     using std::modulus;
     using std::multiplies;
     using std::negate;
-    using std::not1;
-    using std::not2;
     using std::not_equal_to;
     using std::plus;
-    using std::unary_negate;
 
-#if ! defined BSLS_LIBRARYFEATURES_HAS_CPP17_DEPRECATED_REMOVED
+#if !defined(BSLS_LIBRARYFEATURES_HAS_CPP17_DEPRECATED_REMOVED)
     // These names are removed by C++17
     using std::binary_function;
     using std::bind1st;
@@ -69,6 +65,14 @@ namespace bsl {
     using std::unary_function;
 #endif
 
+#if !defined(BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED)
+    // These names are removed by C++20
+    using std::binary_negate;
+    using std::not1;
+    using std::not2;
+    using std::unary_negate;
+#endif
+
 #ifdef BSLS_LIBRARYFEATURES_HAS_CPP11_BASELINE_LIBRARY
     namespace placeholders = std::placeholders;
 

groups/bsl/bsl+bslhdrs/bsl_memory.h

@@ -31,9 +31,6 @@ namespace bsl {
     //  using std::allocator;
     //..
 
-    using std::get_temporary_buffer;
-    using std::raw_storage_iterator;
-    using std::return_temporary_buffer;
     using std::uninitialized_copy;
     using std::uninitialized_fill;
     using std::uninitialized_fill_n;
@@ -82,6 +79,12 @@ namespace bsl {
     using std::undeclare_reachable;
 #endif // BSLS_LIBRARYFEATURES_HAS_CPP11_GARBAGE_COLLECTION_API
 
+#ifndef BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED
+    using std::get_temporary_buffer;
+    using std::raw_storage_iterator;
+    using std::return_temporary_buffer;
+#endif
+
 #ifndef BDE_OMIT_INTERNAL_DEPRECATED
     // Import additional names expected by existing code, but not mandated by
     // the standard header.  This may get tricky if some standard library

groups/bsl/bsl+bslhdrs/bsl_type_traits.h

@@ -113,11 +113,11 @@ using std::is_object;
 using std::is_scalar;
 using std::is_compound;
 
+
     // 20.10.4.3, type properties:
 using std::is_trivial;
 using std::is_standard_layout;
-using std::is_pod;
-using std::is_literal_type;
+using std::is_pod;      // deprecated by C++20
 using std::is_abstract;
 using std::is_signed;
 using std::is_unsigned;
@@ -172,19 +172,22 @@ using std::aligned_union;
 #endif
 using std::common_type;
 using std::underlying_type;
+
+#if !defined(BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED)
+    // These names are removed by C++20
+using std::is_literal_type;
 using std::result_of;
+#endif
 
 #ifdef BSLS_COMPILERFEATURES_SUPPORT_ALIAS_TEMPLATES
 template <std::size_t LEN, std::size_t ALIGN>
-using aligned_storage_t =
-                        typename std::aligned_storage<LEN, ALIGN>::type;
+using aligned_storage_t = typename std::aligned_storage<LEN, ALIGN>::type;
     // 'aligned_storage_t' is an alias to the return type of the
     // 'std::aligned_storage' meta-function.
 
 #ifdef BSLS_COMPILERFEATURES_SUPPORT_VARIADIC_TEMPLATES
 template <std::size_t LEN, class... TYPES>
-using aligned_union_t =
-                       typename std::aligned_union<LEN, TYPES...>::type;
+using aligned_union_t = typename std::aligned_union<LEN, TYPES...>::type;
     // 'aligned_union_t' is an alias to the return type of the
     // 'std::aligned_union' meta-function.
 
@@ -205,22 +208,24 @@ using make_unsigned_t = typename std::make_unsigned<TYPE>::type;
     // 'std::make_unsigned' meta-function.
 
 template <class TYPE>
-using remove_all_extents_t =
-                           typename std::remove_all_extents<TYPE>::type;
+using remove_all_extents_t = typename std::remove_all_extents<TYPE>::type;
     // 'remove_all_extents_t' is an alias to the return type of the
     // 'std::remove_all_extents' meta-function.
 
-template <class TYPE>
-using result_of_t = typename std::result_of<TYPE>::type;
-    // ' result_of_t' is an alias to the return type of the
-    // 'std::result_of' meta-function.
-
 template <class TYPE>
 using underlying_type_t = typename std::underlying_type<TYPE>::type;
     // 'underlying_type_t' is an alias to the return type of the
     // 'std::underlying_type' meta-function.
 #endif
 
+#if !defined(BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED)
+    // These names are removed by C++20
+template <class TYPE>
+using result_of_t = typename std::result_of<TYPE>::type;
+    // ' result_of_t' is an alias to the return type of the
+    // 'std::result_of' meta-function.
+# endif
+
 #ifdef BSLS_LIBRARYFEATURES_HAS_CPP14_BASELINE_LIBRARY
 using std::is_null_pointer;
 using std::is_final;
@@ -287,50 +292,24 @@ template <class TYPE>
 BSLS_KEYWORD_INLINE_VARIABLE
 constexpr bool is_standard_layout_v = std::is_standard_layout<TYPE>::value;
 
-// ----------------------------------------------------------------------------
-
-#if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000 &&  \
+# if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000 && \
     BSLS_COMPILERFEATURES_CPLUSPLUS >= 202002L
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#endif
+#   pragma GCC diagnostic push
+#   pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+# endif
 
 template <class TYPE>
-#if BSLS_COMPILERFEATURES_CPLUSPLUS >= 202002L
+# if BSLS_COMPILERFEATURES_CPLUSPLUS >= 202002L
 BSLA_DEPRECATED  // Warn of using 'bsl::is_pod_v' even though we suppress
                  // warnings of using 'std::is_pod' in this implementation.
-#endif // C++20
+# endif // C++20
 BSLS_KEYWORD_INLINE_VARIABLE
 constexpr bool is_pod_v = std::is_pod<TYPE>::value;
 
-#if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000 &&  \
+# if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000 && \
     BSLS_COMPILERFEATURES_CPLUSPLUS >= 202002L
-#pragma GCC diagnostic pop
-#endif
-
-// ----------------------------------------------------------------------------
-
-#if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000 &&  \
-    BSLS_COMPILERFEATURES_CPLUSPLUS >= 201703L
-#pragma GCC diagnostic push
-#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
-#endif
-
-#if BSLS_COMPILERFEATURES_CPLUSPLUS < 202002L
-template <class TYPE>
-BSLA_DEPRECATED  // Warn of using 'bsl::is_literal_type' even though we
-                 // suppress warnings of using 'std::is_pod' in this
-                 // implementation.
-BSLS_KEYWORD_INLINE_VARIABLE
-constexpr bool is_literal_type_v = std::is_literal_type<TYPE>::value;
-#else
-    // Removed in C++20
-#endif // Introduced in C++17 already deprecated; removed in C++20.
-
-#if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000 &&  \
-    BSLS_COMPILERFEATURES_CPLUSPLUS >= 201703L
-#pragma GCC diagnostic pop
-#endif
+#   pragma GCC diagnostic pop
+# endif
 
 // ----------------------------------------------------------------------------
 
@@ -470,7 +449,7 @@ template <class TYPE1, class TYPE2>
 BSLS_KEYWORD_INLINE_VARIABLE
 constexpr bool is_base_of_v = std::is_base_of<TYPE1, TYPE2>::value;
 
-#ifdef BSLS_LIBRARYFEATURES_HAS_CPP17_BASELINE_LIBRARY
+# ifdef BSLS_LIBRARYFEATURES_HAS_CPP17_BASELINE_LIBRARY
 template <class ...Bools>
 BSLS_KEYWORD_INLINE_VARIABLE
 constexpr bool conjunction_v = std::conjunction<Bools...>::value;
@@ -529,8 +508,30 @@ template <class TYPE1, class TYPE2>
 BSLS_KEYWORD_INLINE_VARIABLE
 constexpr std::size_t is_nothrow_swappable_with_v =
                     std::is_nothrow_swappable_with<TYPE1, TYPE2>::value;
-#endif
-#endif
+# endif // BSLS_LIBRARYFEATURES_HAS_CPP17_BASELINE_LIBRARY
+
+# if(!defined BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED)
+    // These names are removed by C++20
+#   if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000
+#       pragma GCC diagnostic push
+#       pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+#   endif
+
+template <class TYPE>
+BSLA_DEPRECATED  // Warn of using 'bsl::is_literal_type' even though we
+                 // suppress warnings of using 'std::is_pod' in this
+                 // implementation.
+BSLS_KEYWORD_INLINE_VARIABLE
+constexpr bool is_literal_type_v = std::is_literal_type<TYPE>::value;
+
+#   if defined(BSLS_PLATFORM_CMP_GNU) && BSLS_PLATFORM_CMP_VERSION >= 110000
+#       pragma GCC diagnostic pop
+#   endif
+# endif // BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED
+
+#endif  // BSLS_COMPILERFEATURES_SUPPORT_VARIABLE_TEMPLATES
+
+// ----------------------------------------------------------------------------
 
 #if 0
     // These traits are provided by BDE, and have additional members for
@@ -642,7 +643,7 @@ using std::void_t;
 #endif
 
 // ----------------------------------------------------------------------------
-// Copyright 2019 Bloomberg Finance L.P.
+// Copyright 2022 Bloomberg Finance L.P.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.

groups/bsl/bsls/bsls_libraryfeatures.h

@@ -43,6 +43,7 @@ BSLS_IDENT("$Id: $")
 //  BSLS_LIBRARYFEATURES_HAS_CPP17_PMR: <memory_resource>
 //  BSLS_LIBRARYFEATURES_HAS_CPP17_TIMESPEC_GET: <ctime>
 //  BSLS_LIBRARYFEATURES_HAS_CPP17_ALIGNED_ALLOC: <cstdlib>
+//  BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED: more legacy removed
 //  BSLS_LIBRARYFEATURES_STDCPP_GNU: implementation is GNU libstdc++
 //  BSLS_LIBRARYFEATURES_STDCPP_IBM: implementation is IBM
 //  BSLS_LIBRARYFEATURES_STDCPP_INTELLISENSE: Intellisense is running
@@ -376,7 +377,7 @@ BSLS_IDENT("$Id: $")
 // deprecated in C++14 and will be removed in C++17.
 //
 ///'BSLS_LIBRARYFEATURES_HAS_CPP14_BASELINE_LIBRARY'
-///----------------------------------------------------
+///-------------------------------------------------
 // The 'BSLS_LIBRARYFEATURES_HAS_CPP14_BASELINE_LIBRARY' macro is used to
 // identify whether the current platform's standard library supports a baseline
 // set of C++14 library features (which are defined below).  This is especially
@@ -445,7 +446,7 @@ BSLS_IDENT("$Id: $")
 //:   o MSVC 2015
 //
 ///'BSLS_LIBRARYFEATURES_HAS_CPP17_BASELINE_LIBRARY'
-///----------------------------------------------------
+///-------------------------------------------------
 // This macro is used to identify whether the current platform's standard
 // library supports a baseline set of C++17 library features (which are defined
 // below).  This is especially important in BSL when importing standard library
@@ -659,6 +660,17 @@ BSLS_IDENT("$Id: $")
 // '__cplusplus >= 201703L', standard library implementations often provide
 // configuration flags to expose the deprecated library features.
 //
+///'BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED'
+///---------------------------------------------------
+// The 'BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED' macro is defined for
+// libraries that do not export names removed in C++20, such as
+// 'std::get_temporary_buffer' and `std::result_of`.
+// 'BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED' is generally the
+// negation of 'BSLS_LIBRARYFEATURES_HAS_CPP98_AUTO_PTR'.  Although the removal
+// of deprecated C++20 types is conceptually equivalent to '__cplusplus >=
+// 201703L', standard library implementations often provide configuration flags
+// to expose the deprecated library features.
+//
 ///'BSLS_LIBRARYFEATURES_HAS_CPP11_PROGRAM_TERMINATION'
 ///----------------------------------------------------
 // The 'BSLS_LIBRARYFEATURES_HAS_CPP11_PROGRAM_TERMINATION' macro is defined if
@@ -1083,6 +1095,12 @@ BSLS_IDENT("$Id: $")
     // keep deprecated functions available.
 #endif
 
+#if BSLS_COMPILERFEATURES_CPLUSPLUS >= 202002L
+#define BSLS_LIBRARYFEATURES_HAS_CPP20_DEPRECATED_REMOVED             1
+    // Set when C++20 is detected.  Adjusted below for implementations that
+    // keep deprecated functions available.
+#endif
+
 // ============================================================================
 //                     PLATFORM SPECIFIC FEATURE DETECTION
 // ----------------------------------------------------------------------------

groups/bsl/bsls/bsls_platform.h

@@ -921,6 +921,7 @@ struct Platform {
     struct CpuArmv6 : CpuArm {};
     struct CpuArmv7 : CpuArm {};
     struct CpuArmv8 : CpuArm {};
+    struct CpuArmv9 : CpuArm {};
 
                               // PLATFORM TRAITS
 
@@ -997,6 +998,10 @@ struct Platform {
     #if defined(BSLS_PLATFORM_CPU_ARM_V8)
         typedef CpuArmv8 Cpu;
     #endif
+    #if defined(BSLS_PLATFORM_CPU_ARM_V9)
+        typedef CpuArmv9 Cpu;
+    #endif
+
 };
 
 }  // close package namespace